Systems for capturing, streaming, and/or playing back immersive content, such as to simulate an immersive virtual reality environment, e.g., a three-dimensional (3D) environment, are growing in importance as the hardware for such systems becomes more readily available and the cost of such hardware has been diminishing.
While calibrating individual cameras can be important, the relationship between cameras in a camera pair used to capture images for stereoscopic playback can also be important to the final results as perceived by a user of a playback system.
In order to support 3D imaging it can be desirable to capture images using a pair of cameras, often referred to as a stereoscopic camera pair. While it might seem a simple thing to mount two cameras side by side, proper camera spacing can be difficult to achieve and/or the optical axis of a camera in a camera pair may not have the intended orientation and/or may diverge from one another in an unintentional manner. In the case of captured images for stereoscopic playback where an image captured by one camera may be used as a left eye image and an image captured by a second camera may be used as a right eye image, miss-spacing of the cameras and/or misalignment of the cameras' optical paths can have unsettling effect on a viewer, e.g., user of a playback system.
In order to be able to check and/or confirm the spacing of cameras in a camera pair and/or the alignment of the optical axis of the cameras, there is a need for a straight forward calibration system or apparatus that would allow a user, e.g., an operator, to determine if proper camera spacing has been achieved for a camera pair and/or which would allow a user to check that the alignment of the optical axis is correct. It would be desirable if in at least some embodiments an operator of a camera pair calibration apparatus could be provided with an easy to interpret visual indicator of camera spacing and/or alignment which would allow a user to determine when proper spacing and/or alignment was achieved and/or provide some visual indication of miss-alignment or spacing when the desired alignment and/or spacing was not achieved.